Oil extraction system and oil extraction supervisory system

ABSTRACT

An oil extraction system is provided. The oil extraction system includes a sucker rod pump ( 10 ) provided for a production well ( 2 ) so as to pump up crude oil; a signal detecting section ( 12 ) for detecting a pump-off signal sent from the sucker rod pump ( 10 ); and an injection pump ( 20 ) provided for an injection well ( 3 ) so as to pressure-inject fluid which is used for secondary extraction or tertiary extraction. The pressure injection pump ( 20 ) is operated based on the pump-off signal detected by the signal detecting section ( 12 ).

TECHNICAL FIELD

The present invention relates to an oil extraction system for recovering oil forcibly and an oil extraction supervisory system for supervising an oil extraction system.

BACKGROUND ART

At first, the oil extraction from an underground oil field is performed in the form of production using only natural oil discharge energy or production by artificial oil extraction (e.g., gas lift extraction or pumping extraction) that is not associated with EOR (described later). This is primary extraction.

Then, after the oil production by the primary extraction has decreased, it is attempted to increase the extraction efficiency by applying oil discharge energy to an oil layer artificially by pressure-injecting water or natural gas into the oil layer (water flooding or a gas injection method), which is secondary extraction.

Furthermore, after the secondary extraction, an artificial enhanced oil recovery method is employed to extract oil remaining in the underground crude-oil-containing layer. The enhanced oil recovery method is an extraction method that aims to attain higher replacement efficiency than the ordinary water flooding and gas injection method. Examples of the enhanced oil recovery method are a micelle injection method in which crude-oil is recovered by forming microemulsion by adding surfactant to water and oil such as petroleum or heavy oil and then pressure-injecting the microemulsion into an underground crude-oil-containing layer and a polymer injection method in which the oil extraction efficiency is increased by increasing the viscosity of water by adding, to injection water, a water-soluble polymer substance such as polyacrylamide, poly(alkyl acrylate), poly(alkyl methacrylate), polyacrylonitrile, or xanthan gum (see e.g., Patent document 1). Another example is a microorganism injection method which uses microorganisms. In the microorganism injection method, a microorganism is used which produces a metabolite such as a polymer, a surfactant, carbon dioxide, a methane gas, or an acid. It is expected to attain the same function as the above-described EOR technology. (see e.g., Patent document 2).

As described above, the conventional oil extraction methods are attempting to extract oil efficiently by making full use of various extraction techniques.

Incidentally, as a typical example of a pump for extracting oil, a sucker rod pump 300 as shown in FIG. 3 is used. The sucker rod pump 300 extracts oil in such a manner that a rod 301 to whose tip a plunger (not shown) connected is lowered through a tubing and moved vertically by ground facilities and the movement of the rod is transmitted to the plunger. By virtue of its simplicity, the sucker rod pump 300 is used most widely in land oil fields (see e.g., Patent document 3).

A pump-off phenomenon may occur in the sucker rod pump. A pump-off control method is known in which occurrence of a pump-off phenomenon is detected under prescribed conditions and control is made (see e.g., Patent document 4).

Patent document 1: JP-A-11-236556 (pages 2-5)

Patent document 2: JP-B-6-13699 (pages 2-9)

Patent document 3: Japanese Patent No. 3,184,229 (pages 9-11 and FIG. 7)

Patent document 4: WO 00/66892 (pages 9-17)

DISCLOSURE OF THE INVENTION Problem to Be Solved by the Invention

In recent years, it has come to be studied when to employ extraction methods of what principles in the development of an oilfield to work out a most economical plan as a whole. However, there may occur a case that a clear solution cannot be obtained, that is, a most appropriate production plan cannot always be obtained.

The present invention has been made in view of the above problem, and an object of the invention is to provide an oil extraction system and an oil extraction supervisory system capable of extracting oil efficiently by using a pump-off signal in secondary and tertiary extraction.

Means for Solving the Problem

To solve the above problem, the present invention have been made as follows.

According to the invention set forth in claim 1, an oil extraction system comprises: a sucker rod pump provided for a production well so as to pump up crude oil; a signal detecting section for detecting a pump-off signal sent from the sucker rod pump; and an injection pump provided for an injection well so as to pressure-inject fluid which is used for secondary extraction or tertiary extraction, wherein the injection pump is operated based on the pump-off signal detected by the signal detecting section.

According to the invention set forth in claim 2, the signal detecting section is an inverter for driving a power source of the sucker rod pump.

According to the invention set forth in claim 3, the signal detecting section is a superior controller of an inverter for driving a power source of the sucker rod pump.

According to the invention set forth in claim 4, the pump-off signal is transmitted to an inverter for driving a power source of the injection pump.

According to the invention set forth in claim 5, the fluid is water, a gas, or a surfactant.

According to the invention set forth in claim 6, a microorganism is used in place of the fluid.

According to the invention set forth in claim 7, in an oil extraction system comprising a sucker rod pump provided for a production well so as to pump up crude oil; a signal detecting section for detecting a pump-off signal sent from the sucker rod pump; and an injection pump provided for an injection well so as to pressure-inject fluid which is used for secondary extraction or tertiary extraction, an oil extraction method comprises: detecting the pump-off signal with the signal detecting section; and operating the pressure injection pump based on the detected pump-off signal.

According to the invention set forth in claim 8, the signal detecting section is an inverter for driving a power source of the sucker rod pump.

According to the invention set forth in claim 9, the signal detecting section is a superior controller of an inverter for driving a power source of the sucker rod pump.

According to the invention set forth in claim 10, the pump-off signal is transmitted to an inverter for driving a power source of the injection pump.

According to the invention set forth in claim 11, the fluid is water, a gas, or a surfactant.

According to the invention set forth in claim 12, a microorganism is used in place of the fluid.

According to the invention set forth in claim 13, an oil extraction supervisory system comprises: a sucker rod pump provided for a production well so as to pump up crude oil; an inverter for driving the sucker rod pump; a remote supervisory unit for manipulating the inverter; a first radio communication section connected to the remote supervisory unit; a second radio communication section for performing a radio communication with the radio communication section; and a computer connected to the radio communication section.

According to the invention set forth in claim 14, the command is transmitted at a prescribed cycle.

According to the invention set forth in claim 15, in an oil extraction supervisory system comprising a sucker rod pump provided for a production well so as to pump up crude oil; an inverter for driving the sucker rod pump; a remote supervisory unit for manipulating the inverter; a first radio communication section connected to the remote supervisory unit; a second radio communication section for performing a radio communication with the radio communication section; and a computer connected to the radio communication section, an oil extraction supervisory method comprises: sending a certain command from the computer to the inverter via the second radio communication section; receiving, with the remote supervisory unit, the certain command via the first radio communication section; manipulating the inverter in response to the certain command; and transmitting the manipulation result to the computer via the first and second radio communication sections.

According to the invention set forth in claim 16, the certain command is transmitted at a prescribed cycle.

Advantages of the Invention

According to the inventions recited in claims 1 to 12, in secondary or tertiary extraction, the pump for pressure-injecting water, gas, or surfactant (fluid) or microorganisms and the sucker rod pump for extracting oil can be operated so as to cooperate with each other by using a pump-off detection signal of the inverter. This enables efficient oil extraction.

The inventions recited in claims 13 to 16 make it possible to perform oil production/maintenance management at a distant place.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the configuration of an oil extraction system according to a first embodiment of the present invention.

FIG. 2 shows the configuration of an oil extraction supervisory system according to a second embodiment of the invention.

FIG. 3 illustrates a conventional sucker rod pump.

DESCRIPTION OF SYMBOLS

-   1: Underground crude-oil-containing layer (oil layer) -   2: Production well -   3: Injection well -   10: Sucker rod pump -   11: Motor -   12: First inverter -   20: Injection pump -   21: Motor -   22: Second inverter -   23: Signal transmission section -   51: Communication interface -   52: Remote supervisory unit -   53: Radio communication section -   60: Central supervisory system -   61: Radio communication section -   62: Communication interface -   63: Computer -   300: Sucker rod pump -   301: Rod

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be hereinafter described with reference to the drawings.

Embodiment 1

FIG. 1 shows the configuration of an oil extraction system according to the invention. The following description will be made with an assumption that oil is extracted by water flooding. However, the invention can be applied to any injection method in the case of secondary or tertiary extraction.

In FIG. 1, reference numeral 1 denotes an underground crude-oil-containing layer (oil layer), numeral 2 denotes a production well to be a well for extracting oil, and numeral 3 denotes an injection well for injecting water.

Reference numeral 10 denotes a sucker rod pump for pumping up crude oil and numeral 11 denotes a motor serving as a power source of the sucker rod pump 10. Reference numeral 12 denotes a first inverter for driving the motor 11. The first inverter 12 can detect a pump-off signal according to a known technique.

Reference numeral 20 denotes an injection pump for injecting water, numeral 21 denotes a motor serving as a power source of the injection pump 20, and numeral 22 denotes a second inverter for driving the motor 21. Reference numeral 23 denotes a signal transmission section for transmitting a pump-off signal from the first inverter 12 to the second inverter 22 and is composed of a transmitter, a signal line, and a receiver (not shown).

The operation of the above-configured oil extraction system according to the invention will be described below.

As the sucker rod pump 10 continues to pump up crude oil, the oil layer pressure gradually decreases, and thus the oil extraction efficiency gradually lowers. As the oil layer pressure decreases, a pump-off-phenomenon becomes more prone to occur.

When a pump-off signal is detected by the first inverter 12, the signal is transmitted to the second inverter 22 via the signal transmission section 23. That is, the first inverter serves as a pump-off signal detecting section. When receiving the pump-off signal, the second inverter 22 starts pressure-injecting water (fluid).

As a result, the oil layer pressure is recovered and stable oil extraction is enabled in the production well.

Although in this embodiment the first inverter detects a pump-off phenomenon, a superior controller (not shown) may detect the pump-off phenomenon or a sensor provided for the sucker rod pump may detect the pump-off phenomenon directly. Although a pump-off signal detected by the first inverter is transmitted to the second inverter 22 directly, there is no problem if a condition is met that the second inverter can be operated based on the pump-off signal. That is, there is no problem if the pump-off phenomenon is detected by a certain means and then pressure injection of water is performed based on the detection result.

It is not indispensable to start operating the second inverter immediately after detecting the pump-off phenomenon. Operation of the second inverter may be started when the pump-off phenomenon has been detected a prescribed number of times or when the number of times of detection per unit time has exceeded a prescribed value.

As described above, in secondary or tertiary extraction, the pump for pressure-injecting water, gas, or surfactant (fluid) or microorganisms and the sucker rod pump for extracting oil can be operated so as to cooperate with each other by using a pump-off detection signal of the inverter. This enables efficient oil extraction.

Embodiment 2

FIG. 2 shows the configuration of an oil extraction supervisory system according to a second embodiment. A component having the same component in the first embodiment is given the same reference numeral and will not be described below in detail.

In the figure, reference numeral 51 denotes a communication interface, which is a communication interface card that allows the first inverter 12 to exchange data with a remote supervisory unit (described later). Reference numeral 52 denotes the remote supervisory unit which receives a command from a central supervisory system and manipulates the inverter in response to the content of the command. Reference numeral 53 denotes a radio communication section which serves to send and receive a radio signal.

Reference numeral 60 denotes the central supervisory system which is composed of a radio communication section 61, a communication interface 62, and a computer 63.

With the above configuration, when a certain command is sent from the computer 63, command data is transmitted to the remote supervisory unit 52 via the radio communication sections 61 and 53.

The remote supervisory unit 52 manipulates the inverter in response to the command and returns result data to the computer 63.

For example, if the computer 63 sends out a rotating speed read command, the remote supervisory unit 52 reads out rotating speed information that is managed by the inverter and returns it to the computer 63.

If commands are transmitted periodically, result data are acquired periodically and hence data monitoring is enabled.

Accordingly, the operation state of the inverter is checked regularly by the computer 63, so that it is made possible to supervise and manage the oil extraction amount/variation of the entire oil field, the oil extraction amount/variation, operation state, maintainability, availability, etc. of each sucker rod pump.

Although in this embodiment the communication interface is provided inside the first inverter, it may be provided outside the first inverter.

As described above, the supervision using radio communication makes it possible to perform oil production/maintenance management at a distant place. 

1. An oil extraction system comprising: a sucker rod pump provided for a production well so as to pump up crude oil; a signal detecting section for detecting a pump-off signal sent from the sucker rod pump; and an injection pump provided for an injection well so as to pressure-inject fluid which is used for secondary extraction or tertiary extraction, wherein the injection pump is operated based on the pump-off signal detected by the signal detecting section.
 2. The oil extraction system according to claim 1, wherein the signal detecting section is an inverter for driving a power source of the sucker rod pump.
 3. The oil extraction system according to claim 1, wherein the signal detecting section is a superior controller of an inverter for driving a power source of the sucker rod pump.
 4. The oil extraction system according to claim 1, wherein the pump-off signal is transmitted to an inverter for driving a power source of the injection pump.
 5. The oil extraction system according to claim 1, wherein the fluid is water, a gas, or a surfactant.
 6. The oil extraction system according to claim 1, wherein a microorganism is used in place of the fluid.
 7. In an oil extraction system comprising a sucker rod pump provided for a production well so as to pump up crude oil; a signal detecting section for detecting a pump-off signal sent from the sucker rod pump; and an injection pump provided for an injection well so as to pressure-inject fluid which is used for secondary extraction or tertiary extraction, an oil extraction method comprising: detecting the pump-off signal with the signal detecting section; and operating the pressure injection pump based on the detected pump-off signal.
 8. The oil extraction method according to claim 7, wherein the signal detecting section is an inverter for driving a power source of the sucker rod pump.
 9. The oil extraction method according to claim 7, wherein the signal detecting section is a superior controller of an inverter for driving a power source of the sucker rod pump.
 10. The oil extraction method according to claim 7, wherein the pump-off signal is transmitted to an inverter for driving a power source of the injection pump.
 11. The oil extraction method according to claim 7, wherein the fluid is water, a gas, or a surfactant.
 12. The oil extraction method according to claim 7, wherein a microorganism is used in place of the fluid.
 13. An oil extraction supervisory system, comprising: a sucker rod pump provided for a production well so as to pump up crude oil; an inverter for driving the sucker rod pump; a remote supervisory unit for manipulating the inverter; a first radio communication section connected to the remote supervisory unit; a second radio communication section for performing a radio communication with the first radio communication section; and a computer connected to the second radio communication section.
 14. The oil extraction supervisory system according to claim 13, wherein a certain command is transmitted from the computer to the inverter via the second radio communication section at a prescribed cycle.
 15. In an oil extraction supervisory system comprising a sucker rod pump provided for a production well so as to pump up crude oil; an inverter for driving the sucker rod pump; a remote supervisory unit for manipulating the inverter; a first radio communication section connected to the remote supervisory unit; a second radio communication section for performing a radio communication with the first radio communication section; and a computer connected to the second radio communication section, an oil extraction supervisory method comprising: sending a certain command from the computer to the inverter via the second radio communication section; receiving, with the remote supervisory unit, the certain command via the first radio communication section; manipulating the inverter in response to the certain command; and transmitting the manipulation result to the computer via the first and second radio communication sections.
 16. The oil extraction supervisory method, wherein the certain command is transmitted at a prescribed cycle. 